1. Field of the Invention
The present invention generally relates to control switches, and more particularly to a slide-type switch intended for use as a light dimmer control.
2. Description of the Prior Art
Power switches are manufactured in all shapes and sizes for a sundry of different purposes. The present invention is directed to a particular power switch which, although intended for use as a light dimmer, could be used with motors and in other applications. The simplest electrical switches of the type referred to herein generally consist of two or more wires for connection to an external power source, a pair of metal contacts connected to these wires, and a lever or button used to actuate the contacts betweeen open and closed states.
There are several different types of light switches. These include knife switches, mercury switches, turnstile type switches, tumbler switches, push-button switches and electromagnetic switches, all familiar to those skilled in the art. A network of lights may be managed by a single rotary power switch having a plurality of contacts. For light dimming circuits, early switches incorporated a rheostat or potentiometer for regulating the power transmitted to the light bulb. Modern dimmers use a triac firing circuit which generates considerably less heat and power loss than the older potentiometer configuration, although a variable resistor is still employed to adjust the firing range of the triac.
Several problems arise in the manufacture, installation, and use of dimmer switches. One such problem occurs in slide-type dimmers. The slide knob extends outward from the internal mechanisms of the switch, leaving an unsightly gap which peers inside the device. This relates to the manner in which the knob is coupled to the internal potentiometer. Another problem concerns the full "off" setting in a triac firing circuit. Rather than completely shutting off current flow for the full "off" setting, some circuits merely use the triac as a gate, resulting in excessive heat loss, which can further cause short circuits or other failure. Finally, the switch manufacturer must often fabricate a special face plate to accomodate the slide knob, which typically does not conform to standard wall switch face plates. This increases the cost of production of the unit and, consequently, the total cost to the consumer.
It would, therefore, be desirable and advantageous to devise a light switch which has an improved linkage between the slide knob and the internal circuitry, as well as including in the linkage means to totally disconnect the power supply for "full off". The switch should also be adaptable to standard wall face plates.